Prefabricated trusses are often used in the construction of building structures because of their strength, reliability, low cost, and ease of use. The trusses are typically assembled in a factory using machinery for mass-fabrication of individual truss components. The trusses are assembled, for example, on large assembly tables and then shipped to construction sites.
A prefabricated truss typically includes truss members coupled by nailing plates. Each truss member has a first surface and a second surface, and the truss members are pre-cut for a predefined truss configuration. In assembling the truss, the truss members are arranged on a long truss assembly table and nailing plates are placed over the first surface of the truss members. The plates are then pressed into the truss members using, for example, a roller or a vertical press. The truss is then manually flipped over and nailing plates are positioned over the second face of the truss members and pressed thereto. The completed truss is then removed from the assembly table.
Modern gantry presses, or roller presses, include a gantry frame that travels on two guide tracks mounted to the floor along each side of the truss table. A roller is mounted to the gantry frame at a predetermined distance above a truss table worksurface so that as the gantry frame is moved along the guide tracks, the roller presses the nailing plates into the truss members. The gantry press typically presses the nailing plates into the wood truss members to a depth of 50-80% of the total length of the nailing plate projections. The truss may then be passed through a finishing press, which includes a pair of nip rollers, to fully press the nailing plates into the truss members.
The installation of the gantry press guide tracks is critical in the proper operation of the gantry press. In a typical installation, the guide tracks are spaced away from the sides of the truss table to provide adequate clearance for the gantry press. Since the gantry press rides on the guide tracks, the tracks must be level and true with respect to the truss table worksurface. Due to the size and weight of the gantry press, the guide tracks must be securely fastened to the floor and made of a suitable material, typically, steel. During use of the truss table, an operator is required to place the truss members and nailing plates on the truss table worksurface, requiring the operators to step over the guide tracks, if possible, or stand farther from the table and extend the truss members and nailing plates an additional distance. Due to the size and spacing of the guide tracks, easy access to the truss table worksurface is impeded and throughput is reduced.
It would be desirable to provide an apparatus which enables fabricating a truss without requiring that guide tracks be placed on the floor next to the truss table. It would also be desirable to provide an apparatus which does not require a finishing roller to fully press in the nailing plates.